Python 3.4 support - add py34 gate
Python 3.4 support - add py34 gate

As we just upgraded our codebase to work on Python 3.4, we would
like to make sure that each new patchset pass the tests on both
py27 and py34 environments.

Change-Id: I51b706c27af177aa76866e1fda84b484588fa996

noorul/os-project-config,openstack-infra/project-config,dongwenjuan/project-config,dongwenjuan/project-config,Tesora/tesora-project-config,noorul/os-project-config,openstack-infra/project-config,Tesora/tesora-project-config